

/**
 * Container Interface.
 * @author Lukas Koell
 * @author David Medenjak
 * @author Johannes Riedmann
 */
 
interface Container {
    /**
     * Adds an item to the container.
     * @param item Item to add.
     */
    public void add(StringTree item);

    /**
     * Gets the next element from the container and removes it.
     * @return Next element.
     */
    public StringTree next();

    /**
     * Checks if an item is left.
     * @return True if it's empty, false if it's not.
     */
    public boolean isEmpty();
}
